Steering system for vehicles on grooved tracks

ABSTRACT

A robotic vehicle for traversing a grooved track is described. The robotic vehicle includes a set of one or more axles; a set of wheels coupled to each axle in the set of one or more axles; one or more motors to rotate the set of one or more axles, including the set of wheels of each axle in the set of axles, to propel the robotic vehicle along the grooved track; and a steering system to manage navigation of the robotic vehicle along the grooved track, wherein the steering system controls rotation of the set of one or more axles along respective pivot points to manage steering of the robotic vehicle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 62/538,575, filed Jul. 28, 2017, which is hereby incorporated by reference.

TECHNICAL FIELD

One or more embodiments described herein relates to a system and method for steering miniature vehicles operating on grooved tracks. Other embodiments are also described herein.

BACKGROUND

Track systems and vehicles designed to navigate on these track systems have been used for transportation and various industrial and consumer applications. Different rail profiles or types of rails may be utilized in such track systems. Some rails are formed using foot-web-head rail structures, such as a bullhead, I-beam, T-shape, U-shape, or other similar styles. Other rails have a groove-based structure comprised of a recessed channel designed to guide the wheels of a vehicle.

Track systems for miniature vehicles, such as toy train systems, are based on the assembly of individual track pieces into custom track configurations for utility or entertainment purposes. Such track systems may also utilize different rail types, which are typically based on concepts similar to their large scale and industrial counterparts although often implemented based on more simplistic embodiments.

Upon the completion of a miniature track assembly, typical applications for such tracks involve movement of vehicles operating along the track for various purposes. These applications/purposes may include transportation, entertainment, and child developmental activities. All of these applications/purposes involve the navigation of the vehicles between different areas of a track in a desired manner that may be ordered or random in nature. More complex tracks may include splits or junctions, which allow the division of a single pathway into multiple pathways and vice versa. In miniature tracks, such as in wooden toy train tracks, the splits may not include any element/device to controllably navigate the vehicles in a desired direction (i.e., to select a pathway). In some miniature tracks, splits in the tracks may include a mechanical switch element allowing the user to manually select the preferred navigation direction (i.e., the preferred pathway), which forces the vehicle to follow the selected choice. In more sophisticated miniature track systems, such as in electric model train systems, track splits are operated using powered electro-mechanical switches, which are controlled by the user via remote controllers or more advanced control systems such as Digital Command Control (DCC) that utilizes electronic decoders placed in individual switch elements. Such advanced systems allow the development of advanced integration and automation of the entire system via computer control.

Therefore, while vehicle navigation control is attainable in advanced miniature track systems via powered switches, the control comes at significantly increased cost and complexity with respect to the setup of such tracks. Simple, non-powered tracks, including most toy systems for children, lack the structure/elements to enable navigation control or require manual switching that may be limiting due to many factors (e.g., the effort involved in implementing, timing requirements, accessibility constraints, etc.).

SUMMARY

A steering method and system for vehicles operating on grooved tracks is described herein. More specifically, such vehicles include electro-mechanical capabilities to operate on groove-based track systems and controllably navigate on track splits/junctions in a desired direction based on an internal steering system and without the reliance on external track switch mechanisms (i.e., the logic for guiding the vehicle is integrated within the vehicle). A vehicle with such a steering system is designed to maintain a passive/loose/free steering state, which allows the vehicle to naturally follow and conform to the curvatures of the track without derailing or losing speed and stalling in certain areas of the track. Additionally, the vehicle's steering system may be temporarily switched into an active/firm/locked steering state, which enables selective left or right steering while the vehicle navigates splits/junctions in the track. The steering system is designed such that a wheel turning angle is optimized for the grooved track junction design (i.e., the angle between the splitting grooves that form the junction). Such a steering system may be comprised of an electro-mechanical actuator assembly with the capability to steer the vehicle's leading/front wheels to the left or to the right to perform a turning maneuver at junctions on the track. The term “leading wheels” refers to the wheels on the front of the vehicle in terms of its movement direction.

The steering system may employ various actuator types that are suitable for enabling the free and locked steering states. For example, the actuators may include one or more of magnet-based actuators or servo-based actuators. If the vehicle has two axles, the steering system may be based on a linked design where the front and rear wheels are turned at the same time to enable either a left or right turn. In one embodiment, the vehicle may also include a set of sensors to allow the vehicle to receive notifications from the track regarding the approaching track junction. The notification may be used to switch the steering state from free to locked using optimal timing. To enable such a notification, particular track regions may be equipped with a special feature detectable by the vehicle's sensor(s). Moreover, such a track feature may include additional information detectable by the vehicle, which may indicate the desired navigation direction. In another embodiment, the vehicle may include a wireless remote control capability enabling the user operating the vehicle to change the steering system's state and set the turning direction preference. The above-described capabilities to control the vehicle's navigation on the grooved track junctions may be used for applications purposes including transportation, delivery, entertainment, and educational activities.

The above summary does not include an exhaustive list of all aspects of the present invention. It is contemplated that the invention includes all systems and methods that can be practiced from all suitable combinations of the various aspects summarized above, as well as those disclosed in the Detailed Description below and particularly pointed out in the claims filed with the application. Such combinations have particular advantages not specifically recited in the above summary.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures use like reference numbers to refer to like elements. Although the following figures depict various exemplary embodiments, alternative embodiments are within the spirit and scope of the appended claims. In the figures:

FIG. 1 shows a vehicle with a steering system on a grooved track, according to one example embodiment.

FIG. 2A shows a cross-section of a dual-grooved track, according to one example embodiment.

FIG. 2B shows a cross-section of a track with a wide single groove, according to one example embodiment.

FIG. 2C shows a cross-section of a track with a narrow single groove, according to one example embodiment.

FIG. 3 shows a dual-grooved track junction, according to one example embodiment.

FIG. 4 shows a component diagram of the vehicle with a steering system, according to one example embodiment.

FIG. 5A shows a vehicle on a grooved track with an optical track marker, according to one example embodiment.

FIG. 5B shows a vehicle on a grooved track with a three-dimensional topography-based track marker, according to one example embodiment.

FIG. 5C shows a vehicle on a grooved track with a radio-frequency identifier-based track marker, according to one example embodiment.

FIG. 6A shows a left-straight track junction, according to one example embodiment.

FIG. 6B shows a straight-right track junction, according to one example embodiment.

FIG. 6C shows a left-right track junction, according to one example embodiment.

FIG. 6D shows a left-straight-right track junction, according to one example embodiment.

FIG. 7 shows an optimal steering angle based on the vehicle and curvature properties of the track, according to one example embodiment.

FIG. 8A shows a centered magnetic steering system in a loose/free state, according to one example embodiment.

FIG. 8B shows a steered magnetic steering system in a firm/locked state, according to one example embodiment.

FIG. 9A shows a centered servo-based steering system in a loose/free state, according to one example embodiment.

FIG. 9B shows a steered servo-based steering system in a loose/free state, according to one example embodiment.

FIG. 9C shows a steered servo-based steering system in a firm/locked state, according to one example embodiment.

FIG. 10 shows a method for operating the vehicle with a steering system on a grooved track, according to one example embodiment.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known circuits, structures and techniques have not been shown in detail in order not to obscure the understanding of this description. Those of ordinary skill in the art, with the included descriptions, will be able to implement appropriate functionality without undue experimentation.

References in the specification to “one embodiment,” “an embodiment,” “an example embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

In the following description and claims, the terms “coupled” and “connected,” along with their derivatives, may be used. It should be understood that these terms are not intended as synonyms for each other. “Coupled” is used to indicate that two or more elements, which may or may not be in direct physical or electrical contact with each other, co-operate or interact with each other. “Connected” is used to indicate the establishment of communication between two or more elements that are coupled with each other or a direct physical connection.

FIG. 1 shows a vehicle 101 (sometimes referred to as a “robotic vehicle”) with a steering system 111 navigating a segment of a track 103 with grooves 105, according to one example embodiment. As shown, the segment of the track 103 includes a junction 107 where a single pair of grooves 105 splits into two pairs of grooves 105 (i.e., one pathway along the track splits into two pathways). The grooves 105 may operate as rails to guide the vehicle 101 along the track 103. The vehicle 101 has a front axle 121 and a rear axle 131 with a pair of wheels on each axle 121 and 131. In other embodiments, the vehicle 101 may have only a single axle complemented with skid/sliding element(s) to provide the vehicle 101 balance while navigating the track 103. Additionally, each axle may have one wheel complemented with skid/sliding element(s) on either/both sides of the wheel to provide the vehicle 101 balance while navigating the track 103. According to one embodiment, the front axle 121 may be coupled with or be a part of the steering system 111 that is capable of rotating the axle 121 about the axis/pivot point 123, which is positioned centrally at the midpoint of the front axle 121. The rear axle 131 may also be able to rotate about the axis/pivot point 133 to assist a steering maneuver of the vehicle 101. As will be described in greater detail below, such rotating movements, which are enabled by the steering system 111, allow the vehicle 101 to controllably steer on the grooved junctions 107 of the track (e.g., follow a set of grooves 105 at a junction 107 on the track 103). The use of such a vehicle 101 with a steering system 111 on a grooved track 103 may provide additional navigation possibilities when the vehicle 101 can drive to desired locations of the track 103 in a controlled and predictable manner. For example, this additional navigation control may extend to transportation, delivery, gamified entertainment, and/or educational applications/purposes. Various elements of the vehicle 101 operating on groove-based tracks 103 (e.g., the track 103 with the grooves 105) will be described in greater detail below by way of example.

As noted above, the vehicle 101 includes a steering system 111 designed for groove-based tracks 103 (e.g., the track 103 with the grooves 105). The grooves 105 of the track 103 are recessed channels running along at least one side of the track 103 and the vehicle 101 is designed to have complementary wheels. Namely, the wheels of the vehicle 101 are designed to fit within the recessed grooves 105 for proper operation and compatibility. For example, FIG. 2A depicts a cross-section of a dual groove 105 based track 103A for the vehicle 101 with wheels individually conforming to or otherwise fitting within the grooves 105. FIG. 2B shows another embodiment of a groove-based track 103B with a single groove 105, where the wheels of the vehicle 101 fit within and run inside the groove 105. In particular, the wheels of the vehicle 101 fit within the channel created or defined by the groove 105 and the vehicle 101 is guided by the outer walls of the groove 105. FIG. 2C shows yet another embodiment of a groove-based track 103C with a single groove 105 designed for vehicles 101 that have a single wheel on each axle (e.g., a single wheel on axle 121 and/or a single wheel on axle 131). Such vehicles 101 may include skid/sliding elements 213 which help balance the vehicle 101 while the vehicle 101 traverses the track 103C. In this embodiment, the groove 105 on the track 103C is narrower than the groove 105 on the track 103B.

As described above, the various embodiments of the tracks 103 may be based on one or more grooves 105. The grooved nature of the tracks 103 is an element that allows the vehicle 101 to steer on junctions 107 in the track 103 in desired directions based on an internal steering system 111 of the vehicle 101 and without reliance on external switching mechanisms integrated into the track 103. FIG. 3 shows a segment of a track 103 with dual grooves 105, which includes a junction 107. At the junction 107, the track 103 splits into two directions/pathways such that a single pair of grooves 105 is split into two pairs of grooves 105. Such a junction 107 does not obstruct the movement of the vehicle 101 and the navigational direction of the vehicle 101 on such a junction 107 is solely dependent on the rotational position of the front axle 121 about the axis/pivot point 123.

Unlike other vehicles, such as cars, that need to be actively steered to maintain their desired navigational direction, track-based vehicles (e.g., the vehicle 101) are guided by the shape and curvatures of the tracks they drive on. The vehicle 101 with a steering system 111 is designed to maintain a free/passive/loose steering state, which allows the vehicle to naturally follow and conform to the curvatures of the grooves 105 of the track 103 without derailing, losing speed, and/or stalling in certain areas/segments of the track 103. However, the steering system 111 may be temporarily switched into a locked/active/firm steering state to enable selective left or right steering capability while the vehicle 101 is navigating a junction 107 of the track 103. In particular, in the active state, the steering system 111 rotates the front axle 121 about the axis/pivot point 123 to cause the vehicle 101 to turn either left or right. This turning at a junction in the track 103 causes the vehicle 101 to select and/or move along a particular set of grooves 105 (i.e., a pathway) offered by a junction. The design of such a steering system 111 will be described in greater detail below by way of example.

FIG. 4 shows a component diagram of a vehicle 101 with a steering system 111, according to one example embodiment. In the example embodiment shown in FIG. 4, the vehicle 101 may be any device that uses an electro-mechanical mechanism 409 for propulsion, movement, and/or navigation. The vehicle 101 may also include a set of track sensors 405, which allow the vehicle 101 to detect various track markers positioned before junctions 107 on the track 103 or in other areas of the track 103. Such detected track markers may provide notifications to the vehicle 101 about an approaching junction 107 to prepare the vehicle 101 for a steering maneuver.

FIGS. 5A, 5B and 5C show examples of different track marker types detectable by the track sensors 405 of the vehicle 101. FIG. 5A provides an example of a vehicle 101 with a set of optical track sensors 405A capable of detecting the track marker 501A based on the surface color, shape, or a two-dimensional (2D) pattern printed or otherwise formed on the surface of the track marker 501A. Such optical track sensors 405A may be based on phototransistors/photodiodes, red-green-blue (RGB) digital color sensors, low resolution cameras, and other optical sensor types capable of detecting a particular type of an optical track marker 501A used on the track 103. FIG. 5B shows an example of another type of a track marker 501B, which includes one or more three-dimensional (3D) elements. The 3D elements of the track marker 501B extrude/extend/protrude upwards from the surface of the track 103 and a surface of the track marker 501B. Such track markers 501B are designed such that the extending/protruding element, which extends/protrudes from the surface of the track marker 501B, is shorter than the maximum clearance height between the bottom of the vehicle 101 and the track 103 such that the vehicle 101 can pass over the track marker 501B without obstructing movement of the vehicle 101. However, the extruding/extending/protruding 3D elements of the track marker 501B are designed to be detectable by the track sensor 405B of the vehicle 101. Such track sensors 405B may include one or more mechanical buttons facing the track marker 501B from the bottom of the vehicle 101 (i.e., one or more mechanical buttons oriented toward the track 103 when the vehicle 101 is placed on the track 103 to navigate along the track 103). In this embodiment, when the vehicle 101 passes over the track marker 501B, the track sensor 405B is momentarily compressed/depressed or triggered by the extruding/extending/protruding 3D elements of the track marker 501B in a manner that allows the vehicle 101 to recognize the presence of the track marker 501B. FIG. 5C shows yet another example of a track marker 501B. The track marker 501C shown in FIG. 5C may be based on or may include a radio-frequency identifier (RFID), which is detectable by the vehicle 101 using the track sensor 405C. In this embodiment, the track sensor 501C is comprised of a RFID reader component. While all of these examples described above show placement of the track markers 501 in the center of the track 103 between the grooves 105, in other embodiments (not shown) such track markers 501 may be placed off-center or along on one of the sides of the track 103. In such embodiments, the vehicle 101 may include track sensors 405 placed off-center or on the sides of the vehicle 101 to detect the track markers 501.

Returning back to FIG. 4, the electro-mechanical mechanism 409 may include one or more motors 419 that are coupled to wheels of the vehicle 101. The motors 419 cause the wheels to turn and propel the vehicle 101 around/along the track 103. As was described previously, the wheels of the vehicle 101 may be complementary to a set of grooves 105 of the track 103. The motors 419 may be controlled by one or more motor controllers (not shown), which control the speed of rotation of the motors 419 (e.g., rounds per minute). As used herein, the term engine may be used synonymously with the term motor and shall designate a machine that converts one form of energy into mechanical energy. For example, the motors 419 may be electrical motors/engines that convert electricity stored in a battery unit 429 of the vehicle 101 into mechanical energy. The motors 419 power the movement of the vehicle 101 on/along the track 103 in a pre-programmed, remotely controlled, or autonomous fashion. As used herein, autonomous movement is an operating mode that does not involve human interaction or involves minimal human interaction. For example, a human user may turn on the vehicle 101 (e.g., toggle a power switch of the vehicle 101) and place the vehicle 101 on the track 103. After being placed on the track 103, the vehicle 101 may traverse various portions/areas of the track 103 according to an autonomous algorithm (e.g., the vehicle 101 may utilize inputs from the track sensors 501 (e.g., sensor data) to detect the track junctions 107 and autonomously choose the navigation route/pathway along the track 103, for example, based on a random choice of movement direction on the above mentioned junctions 107).

As shown in FIG. 4, the vehicle 101 may include a processor 401 and a memory unit 407. The processor 401 and the memory unit 407 are used here to represent a suitable combination of programmable data processing and storage components that perform the operations needed to implement the various functions and operations of the vehicle 101. For example, as will be described in greater detail below, the memory unit 407 may include a steering control module 427 for autonomously controlling the vehicle 101 to steer along pathways on the track 103 with the help of track markers 501 positioned along the track 103 at a certain distance ahead of track junctions 107. The processor 401 may be a special purpose processor such as an application-specific integrated circuit (ASIC), a general purpose microprocessor or a microcontroller, a field-programmable gate array (FPGA), a digital signal controller, or a set of hardware logic structures (e.g., filters, arithmetic logic units, and dedicated state machines), while the memory unit 407 may refer to any suitable combination of microelectronic, non-volatile random access memory and flash memory circuits, which may be internal or external to the processor 401. In certain embodiments, an operating system may be stored in the memory unit 407 in addition to the steering control module 427. Application programs specific to the various functions of the vehicle 101 may be stored in the memory unit 407, which are to be run or executed by the processor 401 to perform the various functions and operations of the vehicle 101. For example, as noted above, a steering control module 427 may be stored in the memory unit 407 and may be run/executed by the processor 401. The steering control module 427 may perform various functions/operations associated with enabling of a locked/active/firm steering state in the steering system 111 of the vehicle 101, which results in the movement of the vehicle 101 in a desired direction/pathway on track junctions 107, as described in greater detail below.

In addition to notifications of track junctions 107 based on the track markers 501 and sensor data received from track sensors 405, as shown in FIG. 4, the vehicle 101 may also include a wireless communication module 403 that may be used to receive notifications or commands sent by (i) a user of the vehicle 101 who is controlling the vehicle 101 remotely via a companion software application or (ii) a software application containing a control program, running on an external device wirelessly connected to the vehicle 101 and communicating using an application programming interface (API). For example, such a wireless connection that is employed by the wireless communication module 403 may be based on various communication technologies, including one or more of infrared (IR), Bluetooth, Wi-Fi, etc.

Although not shown in FIG. 4, in some embodiments, the vehicle 101 may also include components to provide audio-visual feedback to a user of the track 103 and/or a vehicle 101. For example, the vehicle 101 may include a speaker for playing back sounds stored in the memory unit 407 in conjunction with various actions of the vehicle 101 (e.g., output a sound upon detecting a track marker 501 or upon the vehicle 101 completing a steering maneuver). In another example, the vehicle 101 may include single or multi-color light emitting diodes (LEDs) to provide visual feedback to the user of the track 103 and/or the vehicle 101, and/or perform light animations upon detecting a track marker 501 or upon the vehicle 101 completing a steering maneuver.

As mentioned previously and as shown in FIG. 4, the electro-mechanical mechanism 409 of the vehicle 101 includes a steering system 111. Such a steering system 111 is designed to enable the rotation of the wheels of the vehicle 101 to consistently perform steering maneuvers in/along the desired direction/pathway of junctions 107. Moreover, as previously described, groove-based tracks 103 may require the steering system 111 to be able to operate in both free and locked steering states for the vehicle 101 to be able to appropriately move around and along the track 103 (i.e., to be able to consistently steer in the desired direction/path (e.g. steer left, right, or go straight) at each track junction 107) without being obstructed and/or derailed. Assuming a vehicle 101 has more than one axle (e.g., the axles 121 and 131), for the vehicle 101 to steer in the desired direction/path at a track junction 107 of a groove-based track 103, a steering maneuver may be performed by the wheel(s) of the vehicle 101 in the leading position (i.e., the wheel(s) at the front of the vehicle 101 in terms of its movement direction on the track 103).

To minimize the chance of derailing or obstructing the vehicle 101, track systems may utilize smooth and gradual transitions between straight and curved areas/portions of the track 103. In these embodiments, the track junctions 107 may include shallow angles formed by various combinations of straight and curved pieces of the track 103. For example, FIGS. 6A and 6B show how a combination of a straight portions of the track 103 may be combined with a curved portion of the track 103 to form a left-straight junction 107A and a straight-right junction 107B. Two curved portions of the track 103 heading in opposite directions can form a left-right junction 107C, as shown in FIG. 6C. Similarly, a three-way left-straight-right junction 107D may be formed using straight and curved portions of the track 103, as shown in FIG. 6D.

To achieve optimal steering performance on a junction 107 while the vehicle 101 enters a curved portion of the track 103 based on a curvature of a certain radius, the turning angle of the wheels of the vehicle 101 may be optimized based on the wheelbase of the vehicle 101 and the radius of the curvature of the track 103. FIG. 7 shows that when a vehicle 101 is entering and/or moving along a circular curve 707 with a radius 709, the optimal steering angle 705 formed by the front wheel axle 701 and the rear wheel axle 703 is the angle between the tangents of the circular path 707 aligned with the axles 701 and 703. Accordingly, the value of the optimal steering angle 705 increases with an increase of the wheelbase 715 of the vehicle 101 and such an angle 705 is proportional to the ratio of the wheelbase 715 and the radius 709 of the curve 707. Additionally, in embodiments where the width of the wheels of a vehicle 101 are narrower than the width of the grooves 105 of the track 103, the steering angle 705 may be varied within a range proportional to the width difference between the wheels of the vehicle 101 and the grooves 105.

While the choice of the radius 709 of the curve 707 used on a given track 103 may depend on the size of the vehicle 101, the size of the track 103 itself, and associated applications, ensuring that the resultant optimal steering angle 705 is small has numerous advantages. For example, these advantages include the reduction of the possibility of the derailment or obstruction of the vehicle 101 at higher speeds and the simplification of the requirements for the mechanical design of the steering system 111 of the vehicle 101. For instance, when the radius 709 of the curve 707 of the track 103 is significantly larger than the size of the wheelbase 715 of the vehicle 101, the steering system 111 may utilize the rotation of the wheel axles 701 and/or 703 along the axes 711 and/or 713, respectively, based on the shallow optimal steering angle 705. Alternatively, as the required steering angles 705 get larger, the mechanical design of the vehicle 101 may need to utilize a differential steering mechanism (not shown) to balance out the more significant drive torque requirements on the different sides of the vehicle 101 to avoid performance problems.

FIGS. 8A and 8B show an example embodiment of a steering system 111 based on a magnetic actuator formed using an electromagnetic coil 825 and a pair of magnets 821 and 823 in a vehicle 101 with a front axle 801 and a rear axle 803, where each axle 801 and 803 has a pair of wheels. The pair of magnets 821 and 823 may be coupled to the front axle 801 and the rear axle 803 via a frame or housing that surrounds each of the front axle 801 and the rear axle 803. Accordingly, the front axle 801 and the rear axle 803 rotates inside this frame/housing. The electromagnetic coil 825 in the magnetic actuator may be formed of a conducting wire (e.g. a copper wire) wound in a shape of a coil. As electric current passes through the wire, a magnetic field is produced perpendicular to the direction of the current's propagation. The strength of the magnetic field is dependent on factors such as the thickness of the wire, dimensions of the coil 825, the amount of the current, and, assuming the coil 825 has a core, the size and material used as the core. In some magnetic actuators, the coil 825 is oriented and optimized such that the coil 825 is capable of generating a magnetic field to either attract or push away from an element made from a permanent magnet or a ferromagnetic material to generate the desired mechanical actuation. As shown in FIG. 8A, the magnetic actuator used in the steering system 111 utilizes a coil 825 and a pair of permanent magnets 821 and 823, which are oriented to have opposite polarity in relation to the coil 825 (e.g. magnet 821 is oriented to have a positive pole/side pointed at the coil 825 and magnet 823 is oriented to have a negative pole/side pointed at the coil 825, or vice versa). According to this example embodiment, the magnetic actuator is integrated into the steering system 111 such that the coil 825 is attached to the inner housing of the vehicle 101, is centered (e.g., is located on the axis running through the middle of the vehicle 101 along the length of the vehicle 101) and is stationary. The magnets 821 and 823 are integrated into the front axle 801 and can rotate with the front axle 801 along the axle midpoint 811.

As described previously, it may be necessary to steer the leading wheels on a vehicle 101 operating on groove-based tracks 103. Therefore, the placement of the magnetic actuator in the front of the vehicle 101 will enable the vehicle 101 to steer at junctions 107 when the vehicle 101 moves in the front facing direction (i.e., the front axle frame 801 is leading the movement of the vehicle 101). However, the vehicle 101 may also be capable of moving in the reverse direction. While steering while the vehicle 101 is moving in the reverse direction can be accomplished by equipping the steering system 111 with a secondary actuator to control the steering movement of the rear axle 803, the example embodiment of the steering system 111 shown in FIGS. 8A and 8B utilizes a mechanical link 805 that couples the front axle 801 with the rear axle 803 at the midpoint distance between the front axle 801 and the rear axle 803 of the vehicle 101. Such a design allows a synchronized and equal turning of the front axle 801 and the rear axle 803, along the axle midpoint 811 and the axle midpoint 813, respectively, enabled with a single actuator. As used herein, the axle midpoint 811 and the axle midpoint 813 may referred to as the axis/pivot point 811 and axis/pivot point 813, respectively.

It was described previously that free and locked steering states may be used for a vehicle 101 to navigate groove-based tracks 103 and steer when traversing junctions 107. To enable the free steering state in the steering system 111, the coil 825 is kept passive, such that no current is passing through it. As a result, the front axle 801 and the rear axle 803 are free to rotate within a mechanically limited range and assume any position between the vehicle 101 steering to the right (as shown in FIG. 8B) or similarly turning to the left (not shown). The maximum turning angle of the steering system 111 can be optimized for a given track 103 based on the curvature properties of the track 103 and the resultant optimal steering angle 705.

To enable the locked steering state, the coil 825 may be temporarily activated (i.e., current is passed through the coil 825). Depending on whether there is positive or negative charge applied to the coil 825, the direction of the current passing through the coil 825 can be reversed, resulting in a magnetic force which would attract the coil 825 to either magnet 821 or magnet 823, depending on whichever one of the magnet 821 and the magnet 823 is oriented to be positive or negative in relation to the coil 825. FIG. 8B shows an example of the coil 825 attracting the magnet 823 resulting in the vehicle 101 steering to the right, assuming the front axle 801 is forward facing. The placement and the offset chosen for the magnets 821 and 823 may be designed for optimal steering performance of the steering system 111 on a particular design of a track junction 107. For example, the magnets 821 and 823 are placed symmetrically to the left and to the right of the coil 825 and the offset distance from the coil 825 may be optimized such that the steering system 111 is capable of maintaining the locked steering state while maintaining the optimal steering angle 705.

In another example embodiment of the steering system 111, the steering actuator may be based on a servo motor 901 coupled with the front axle 801 via extruding/protruding frame element 905 contained within a bracket 903 permanently attached to the rotating shaft of the servo motor 901, as shown in FIG. 9A. A servo motor may be a rotary or a linear actuator that allows for precise control of angular or linear position, velocity, and acceleration. For example, a servo motor may include a suitable motor which may be coupled to a sensor for position feedback and an electronic controller located internally or externally to the servo motor itself. Examples of motors, which may be used in a servo motor, may include brushed permanent magnet direct current (DC) motors, brushless DC and alternating current (AC) motors, stepper motors, electronically commutated brushless motors, and AC induction motors. The bracket 903 may be made using various materials (e.g. plastics, metals, and their alloys), assembled from a single piece or multiple pieces and has a size and a shape that is optimal for the functional requirements of a steering system 111.

Similar to the function of the magnetic actuator used in the steering system 111 shown in FIGS. 8A and 8B, the steering actuator of FIG. 9A may only enable the steering of the front axle 801 or the rear axle 803, depending on the steering actuator's placement within the mechanical assembly of the vehicle 101. Alternatively, the steering actuator may steer both the front axle 801 and the rear axle 803 together if the front axle 801 and the rear axle 803 are coupled at the link 805.

To enable a free steering state, the servo-based steering system 111 may include or otherwise utilize a bracket 903 that may, for example, have a rounded closed loop shape, which forms an opening with a continuous boundary, as shown in FIG. 9A. While in the free steering state, the servo motor 901 is set to its nominal position, which aligns the bracket 903 such that the extruding/protruding frame element 905 of the front axle 801 is centered within the bracket 903. As such, the bracket 903 is designed to limit the rotational movement of the front axle 801 via the frame element 905. In the free steering state, the front axle 801 can freely turn to the left or to the right until the frame element 905 is stopped by the bracket 903, as shown in FIG. 9B. The size and the shape of the bracket 903 may be designed such that maximum steering angle is optimized for curvatures of the track 103 that the vehicle 101 is designed to operate on. While this example illustrates a rounded closed-loop-shaped bracket 903, such a bracket 903 could as well have a rectangular, triangular, or another continuous boundary forming shape with an open or closed-loop design.

To enable the locked steering state, the servo motor 901 may rotate the bracket 903 in the clockwise or counter-clockwise direction to lock the frame element 905 and steer the vehicle 101. As shown in FIG. 9C, the bracket 903 rotated in the clockwise direction locks the frame element 905 to the left resulting in the vehicle 101 steering to the right, assuming the vehicle 101 is moving in the forward-facing direction. Alternatively, the bracket 903 can be rotated counter-clockwise to steer the vehicle 101 to the left. The rotation angle of the servo motor 901 together with the size and shape of the attached bracket 903 can be designed to use the optimal steering angle 705 for a given track junction 107.

Regardless of the type of the steering system 111, the duration of the locked steering state may be set to an optimal time for a vehicle 101 while the vehicle 101 is passing through the junction 107 based on the application requirements of the vehicle 101 and the track 101 the vehicle 101 uses. For example, such a duration may be determined based on the minimum time necessary for the vehicle 101 to enter and navigate through the junction 107 at its slowest operating speed. In another embodiment, the duration of the locked steering state may be also adaptive based on the speed of the vehicle 101 when the vehicle enters the junction 107. In yet another embodiment, the duration of the locked steering state may be set to a value optimal for a particular nominal junction speed of the vehicle 101. In this example, the vehicle 101 operates on a track 103 with track markers 501 that may temporarily set the speed of the vehicle to a nominal junction speed. This track marker 501 notifies the vehicle 101 of the approaching junction 107 a certain distance ahead such that the vehicle 101 may reduce speed for a specified duration or distance, which corresponds to a length of the junction 107, and alter steering/direction while in the locked steering state. After the vehicle 101 exits the locked steering state, the speed of the vehicle 101 that was used prior to the junction 107 may be resumed.

As shown in FIGS. 8A, 8B, 9A, 9B and 9C, the steering system 111 may also use a torsion spring 807 attached to the inner housing of the vehicle 101 such that the torsion spring 807 is stationary. However, the torsion spring 807 can be coupled to an extruding/protruding element 809 of the front axle 801 such that the torsion spring 807 is increasingly engaged the more the front axle 801 rotates to the left or to the right and away from center (e.g., the front axle 801 is at center when the front axle 801 is parallel to the front face of the vehicle 101). Such a torsion spring 807 is designed to have an optimal firmness to assist the return of the steering to the center resulting in the straightening of the wheels of the vehicle 101. However, the firmness of the torsion spring 807 needs not be balanced such that the torsion spring 807 is soft enough as to not obstruct the movement of the vehicle 101 on curved tracks 103 or interfere with the performance of the magnetic actuator.

Turning now to FIG. 10, a method 1000 will be described for steering the vehicle 101 on groove-based track junctions 107, according to one example embodiment. Although shown and described in a particular order, in some embodiments the operations of the method 1000 may be performed in a different order. For example, in some embodiments, two or more operations of the method 1000 may be performed concurrently or in partially overlapping time periods.

As shown in FIG. 10, the method 1000 may commence at operation 1001 with the vehicle 101 being placed onto the groove-based track 103 such that the vehicle 101 can begin traversing the track 103.

At operation 1003, the vehicle 101 continuously gathers and/or generates track sensor data while traversing the track 103. For example, using the electro-mechanical mechanism 409, the vehicle 101 may traverse the track 103 to move over or otherwise proximate to a track marker 501. During this movement, the track sensors 405 of the vehicle 101 may generate track sensor data corresponding to track markers 501 or other areas of the track 103. The generated track sensor data is continuously processed by the steering control module 427 to determine when a track marker 501 has been detected. When the steering control module 427 determines that the track sensor data corresponds to a track marker 501, this event equates to a notification to the vehicle 101 of a track junction 107 ahead. Alternatively, a notification of a track junction 107 ahead may be received from a user of the vehicle 101 communicating to the vehicle 101 via a companion software application running on an external device that is wirelessly connected to the vehicle 101.

At operation 1005, the steering control module 427 determines if the notification, which is based on a detected track marker 501, includes a specific steering choice instruction (e.g., turn left by a specified degree/amount, turn right by a specified degree/amount, or continue straight along the track 103). If such a steering choice is indicated in the notification, the method 1000 moves to operation 1007 where the vehicle 101 steers in the instructed direction at the track junction 107. Alternatively, if no steering choice instruction is indicated in the notification, the method 1000 moves to operation 1009.

Following operation 1007, the method 1000 returns to operation 1003 and continues navigating the track 103, gathering track sensor data, and/or awaiting further notifications regarding junctions 107 in the track 103.

At operation 1009, the steering control module 427 checks if there is a steering choice instruction available in the memory unit 407. For example, the memory unit 407 may contain a user program or a data array containing a sequence of consecutive steering choice instructions that the vehicle 101 is to follow in a particular order. After executing a choice instruction associated with the first element of the array, upon receiving the next notification of an approaching track junction 107, the vehicle 101 may follow the instruction associated with the second element of the array. In another example, the steering control module 427 may receive a notification about the approaching junction 107 based on the track sensor data while the steering choice instruction may be received by the steering control module 427 from the user via a companion application. Regardless of the source of the instruction, if such a steering choice instruction is present in the steering control module 427, the method 1000 moves to operation 1011 where the vehicle 101 steers in the instructed direction on the track junction 107. Alternatively, if no steering choice instruction is present, the method 1000 moves to operation 1013.

Following operation 1011, the method 1000 returns to operation 1003 and continues navigating the track 103, gathering track sensor data, and/or awaiting further notifications regarding junctions 107 in the track 103.

At operation 1013, the vehicle 101 received a notification of a junction 107 ahead but there is no steering choice instruction available. At this point, the vehicle 101 does not steer left or right and instead proceeds straight at the track junction 107.

Following operation 1013, the method 1000 returns to operation 1003 and continues navigating the track 103, gathering track sensor data, and/or awaiting further notifications regarding junctions 107 in the track 103.

Due to the looped nature of the method 1000, the method 1000 may continue indefinitely until an end condition has been reached (e.g., the end of the track 103 is reached or the vehicle 101 is stopped by a user).

As shown above, several embodiments for a robotic vehicle are described herein. Similar or identical example embodiments are provided below. Example 1 provides an exemplary embodiment of a robotic vehicle for traversing a grooved track including a set of one or more axles; a set of wheels coupled to each axle in the set of one or more axles; one or more motors to rotate the set of one or more axles, including the set of wheels of each axle in the set of axles, to propel the robotic vehicle along the grooved track; and a steering system to manage navigation of the robotic vehicle along the grooved track, wherein the steering system controls rotation of the set of one or more axles along respective pivot points to manage steering of the robotic vehicle.

Example 2 includes the substance of the exemplary robotic vehicle of Example 1, wherein the steering system of the robotic vehicle is configured to set the set of one or more axles in a free state.

Example 3 includes the substance of the exemplary robotic vehicle of Example 2, wherein in the free state a first axle in the set of one or more axles is free to move about a first pivot point such that the first axle is free to turn in response to curves in the grooved track.

Example 4 includes the substance of the exemplary robotic vehicle of Example 3, wherein in the free state a second axle in the set of one or more axles is free to move about a second pivot point such that the second axle is free to turn in response to the curves in the grooved track.

Example 5 includes the substance of the exemplary robotic vehicle of Example 4, wherein the steering system of the robotic vehicle is configured to set the set of one or more axles in a locked state, and wherein in the locked state the first axle is mechanically locked to prevent the first axle from freely rotating about the first pivot point.

Example 6 includes the substance of the exemplary robotic vehicle of Example 5, wherein the steering system enables the locked state in response to receipt of a wireless signal.

Example 7 includes the substance of the exemplary robotic vehicle of Example 5, wherein in the locked state one or more of the first axle and the second axle pivots according to settings by the steering system.

Example 8 includes the substance of the exemplary robotic vehicle of Example 7, wherein the steering system includes a magnetic actuator comprised of a coil, a first magnet, and a second magnet, and wherein the first and second magnets are coupled to the first axle.

Example 9 includes the substance of the exemplary robotic vehicle of Example 8, wherein in the locked state, the steering system applies a current to the coil to cause (1) the first magnet to move to the coil and (2) the first axle to rotate about the first pivot point.

Example 10 includes the substance of the exemplary robotic vehicle of Example 9, wherein in the free state, a current is not applied to the coil.

Example 11 includes the substance of the exemplary robotic vehicle of Example 5, further comprising: a set of sensors to generate sensor data while the robotic vehicle traverses the grooved track; and a steering control module to adjust the steering system based on the sensor data.

Example 12 includes the substance of the exemplary robotic vehicle of Example 11, wherein the steering control module includes sets of data and corresponding sets of actions, and wherein the sets of data include attributes of markers, including one or more of a color and shape of the markers.

Example 13 includes the substance of the exemplary robotic vehicle of Example 12, wherein the sets of actions include one or more of placing the steering system in the locked state, indicating an approaching junction, indicating a junction type of the approaching junction, and indicating a turning direction preference for the approaching junction.

Example 14 includes the substance of the exemplary robotic vehicle of Example 12, wherein the sets of actions includes placing the steering system in the free state.

Example 15 includes the substance of the exemplary robotic vehicle of Example 12, wherein the set of actions includes pivoting the first axle about the first pivot point by a specified angle.

Example 16 includes the substance of the exemplary robotic vehicle of Example 15, wherein the specified angle is proportional to one or more of a length of a wheelbase of the robotic vehicle and a radius of a curvature of the grooved track.

Example 17 includes the substance of the exemplary robotic vehicle of Example 12, wherein the set of sensors includes one or more mechanical buttons oriented toward the grooved track when the robotic vehicle is placed on the grooved track to navigate along the grooved track, and wherein the sets of data include the one or more mechanical buttons being depressed.

Example 18 includes the substance of the exemplary robotic vehicle of Example 12, wherein the set of sensors includes one or more optical sensors.

Example 19 includes the substance of the exemplary robotic vehicle of Example 1, wherein the set of one or more axles includes a front axle and a rear axle, wherein the front axle and the rear axle are coupled together such that movement of the front axle about a front pivot point by the steering system also causes movement of the rear axle about the rear pivot point.

Example 20 includes the substance of the exemplary robotic vehicle of Example 1, wherein the steering system includes a servo based steering actuator coupled to one or more axles in the set of one or more axles for steering of the robotic vehicle.

Some portions of the preceding detailed descriptions have been presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations are the ways used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm is here, and generally, conceived to be a self-consistent sequence of operations leading to a desired result. The operations are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, combined, compared, and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like.

It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. The present disclosure can refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage systems.

The present disclosure also relates to an apparatus for performing the operations herein. This apparatus can be specially constructed for the intended purposes, or it can include a general-purpose computer selectively activated or reconfigured by a computer program stored in the computer. Such a computer program can be stored in a computer readable storage medium, such as, but not limited to, any type of disk including floppy disks, optical disks, CD-ROMs, and magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPROMs, magnetic or optical cards, or any type of media suitable for storing electronic instructions, each coupled to a computer system bus.

The algorithms and displays presented herein are not inherently related to any particular computer or other apparatus. Various general-purpose systems can be used with programs in accordance with the teachings herein, or it can prove convenient to construct a more specialized apparatus to perform the method. The structure for a variety of these systems will appear as set forth in the description below. In addition, the present disclosure is not described with reference to any particular programming language. It will be appreciated that a variety of programming languages can be used to implement the teachings of the disclosure as described herein.

The present disclosure can be provided as a computer program product, or software, that can include a machine-readable medium having stored thereon instructions, which can be used to program a computer system (or other electronic devices) to perform a process according to the present disclosure. A machine-readable medium includes any mechanism for storing information in a form readable by a machine (e.g., a computer). In some embodiments, a machine-readable (e.g., computer-readable) medium includes a machine (e.g., a computer) readable storage medium such as a read only memory (“ROM”), random access memory (“RAM”), magnetic disk storage media, optical storage media, flash memory components, etc.

In the foregoing specification, embodiments of the disclosure have been described with reference to specific example embodiments thereof. It will be evident that various modifications can be made thereto without departing from the broader spirit and scope of embodiments of the disclosure as set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense. 

What is claimed is:
 1. A robotic vehicle for traversing a grooved track, the robotic vehicle comprising: a set of one or more axles; a set of wheels coupled to each axle in the set of one or more axles; one or more motors to rotate the set of one or more axles, including the set of wheels of each axle in the set of axles, to propel the robotic vehicle along the grooved track; and a steering system to manage navigation of the robotic vehicle along the grooved track, wherein the steering system controls rotation of the set of one or more axles along respective pivot points to manage steering of the robotic vehicle.
 2. The robotic vehicle of claim 1, wherein the steering system of the robotic vehicle is configured to set the set of one or more axles in a free state.
 3. The robotic vehicle of claim 2, wherein in the free state a first axle in the set of one or more axles is free to move about a first pivot point such that the first axle is free to turn in response to curves in the grooved track.
 4. The robotic vehicle of claim 3, wherein in the free state a second axle in the set of one or more axles is free to move about a second pivot point such that the second axle is free to turn in response to the curves in the grooved track.
 5. The robotic vehicle of claim 4, wherein the steering system of the robotic vehicle is configured to set the set of one or more axles in a locked state, and wherein in the locked state the first axle is mechanically locked to prevent the first axle from freely rotating about the first pivot point.
 6. The robotic vehicle of claim 5, wherein the steering system enables the locked state in response to receipt of a wireless signal.
 7. The robotic vehicle of claim 5, wherein in the locked state one or more of the first axle and the second axle pivots according to settings by the steering system.
 8. The robotic vehicle of claim 7, wherein the steering system includes a magnetic actuator comprised of a coil, a first magnet, and a second magnet, and wherein the first and second magnets are coupled to the first axle.
 9. The robotic vehicle of claim 8, wherein in the locked state, the steering system applies a current to the coil to cause (1) the first magnet to move to the coil and (2) the first axle to rotate about the first pivot point.
 10. The robotic vehicle of claim 9, wherein in the free state, a current is not applied to the coil.
 11. The robotic vehicle of claim 5, further comprising: a set of sensors to generate sensor data while the robotic vehicle traverses the grooved track; and a steering control module to adjust the steering system based on the sensor data.
 12. The robotic vehicle of claim 11, wherein the steering control module includes sets of data and corresponding sets of actions, and wherein the sets of data include attributes of markers, including one or more of a color and shape of the markers.
 13. The robotic vehicle of claim 12, wherein the sets of actions include one or more of placing the steering system in the locked state, indicating an approaching junction, indicating a junction type of the approaching junction, and indicating a turning direction preference for the approaching junction.
 14. The robotic vehicle of claim 12, wherein the sets of actions includes placing the steering system in the free state.
 15. The robotic vehicle of claim 12, wherein the set of actions includes pivoting the first axle about the first pivot point by a specified angle.
 16. The robotic vehicle of claim 15, wherein the specified angle is proportional to one or more of a length of a wheelbase of the robotic vehicle and a radius of a curvature of the grooved track.
 17. The robotic vehicle of claim 12, wherein the set of sensors includes one or more mechanical buttons oriented toward the grooved track when the robotic vehicle is placed on the grooved track to navigate along the grooved track, and wherein the sets of data include the one or more mechanical buttons being depressed.
 18. The robotic vehicle of claim 12, wherein the set of sensors includes one or more optical sensors.
 19. The robotic vehicle of claim 1, wherein the set of one or more axles includes a front axle and a rear axle, wherein the front axle and the rear axle are coupled together such that movement of the front axle about a front pivot point by the steering system also causes movement of the rear axle about the rear pivot point.
 20. The robotic vehicle of claim 1, wherein the steering system includes a servo based steering actuator coupled to one or more axles in the set of one or more axles for steering of the robotic vehicle. 